The purpose of this study is to investigate the determinants of valid symptom perception in childhood asthma and the relation of symptom perception to asthma morbidity. The specific hypotheses to be tested in the study are: 1) greater validity of self-perceived symptoms is associated with less functional morbidity from asthma; 2) specific psychological and asthma-related determinants affect the sensitivity and specificity of symptom perception in children with asthma; 3) perception of respiratory symptoms is a measurable characteristic that can be evaluated in terms of reliability and validity; 4) perceptual accuracy in a natural or clinical setting is significantly related to perceptual ability measured in a laboratory. Investigation of these objectives will be approached using a cross-sectional prevalence study of validity of self-perception of symptoms in relation to clinical status. Children aged 8-15 will make subjective estimates of their asthma severity immediately prior to pulmonary function testing at multiple times while they live either at a summer camp for children with asthma or a long-term asthma treatment center. The correspondence between subjective and objective measures of pulmonary function in the clinical environment will be compared with results obtained in a laboratory using threshold detection of added resistive loads. The sensitivity and specificity of asthmatic children's self-assessment of symptom state will be quantified and related retrospectively to risk of functional morbidity. Cognitive abilities, anxiety level, tendency toward repression, locus of control, and familial factors will be investigated regarding their role as determinants of sensitivity and specificity of symptom self-perception as a measure of pulmonary function. The stability of individual patterns of self-perception will be studied longitudinally with annual repeated evaluations among those children who return to camp or are rehospitalized. The treatment of childhood asthma increasingly entails self-management as an important factor in influencing the course of the disease. Findings from the proposed study will identify subgroups of children who are at increased risk of misinterpreting, and thus mismanaging, their pulmonary function. Identification of the characteristics of these high risk children will form the basis for subsequent development of an intervention program to improve symptom self-perception, thereby enhancing the children's ability to participate effectively in self-management of their asthma.